1. Field
The disclosed embodiments relate to a method for the determining, on board an aircraft, of an identifier of the communications centre with which the crew of the aircraft wishes to make contact. It enables the automatic recording of the identifier of the communications centre corresponding to the radio communications frequency entered in the cockpit display with a view, especially, to facilitating a resumption of communications. The disclosed embodiments also relate to a system used to implement this method.
The disclosed embodiments can be applied in aeronautics and especially in communications between an aircraft and the exterior.
2. Brief Description of Related Developments
Whether on the ground or in flight, an aircraft has to communicate through a radio link with the exterior, for example with the control tower or with an air-traffic control centre, in order to exchange data relating especially to the movement of the aircraft. In particular, when an aircraft is in flight, the crew on board the aircraft, for example the pilot or the co-pilot, communicates by radio link with the ground staff, for example the air-traffic controller, in order to exchange flight data.
This data may be data on the flight sector, the flight level, the speed of the aircraft, the frequency of transmission/reception of messages to be exchanged with the ground staff, etc. This data may, for example, relate to the VHF or HF frequency of the radio-frequency communications link with the communications centre, especially the ATC frequency in the case of communications for a civilian aircraft, or any other frequency intended for aeronautical use.
Indeed, each area of aeronautical space, such as airports and airspace, is sectorized. Each sector is managed by a communications centre. The term “communication centre” refers to an air-traffic control centre as well as to a communications centre for communications with the airline etc. For example, each sector of airspace is managed by one air-traffic control centre. In a given sector of airspace, therefore, an aircraft has only one air-traffic controller interacting with it. In this sector, the aircraft communicates with the communications centre on a specific HF or VHF frequency channel.
When an aircraft is to leave a sector in order to enter new sector, the crew of the aircraft must know the frequency of the radio channel on which it will communicate with the air-traffic controller of the new sector. The crew of the aircraft must be informed of the radio-frequency of the new sector before leaving the former sector so that it can come into contact with the air-traffic controller of the new sector as soon as it enters this new sector.
For example, when an aircraft reaches the end of a first sector, the air-traffic controller of the first sector sends the crew member in charge of communications on board the aircraft, hereinafter called the pilot, the new VHF or HF frequency on which the pilot will be communicating with the air-traffic controller of the second sector. Generally, the pilot writes this new frequency to a display unit of the cockpit, for example on a radio-frequency instruments control panel. When the pilot receives information on the frequency of the new sector, he knows which sector is concerned. Indeed, using regulations-specified documents such as maps, the pilot generally knows which communications centers he will be communicating with throughout the flight, depending on the maneuvers that he would have to make (for example landing, take-off, cruising etc). In any case, the frequency of the new communications centre is communicated to the pilot by the previous communications centre so that he can prepare to use the frequency that he will have to use for contacting the new control centre, by writing the information to a display unit of the cockpit.
Usually, it is only the frequency of the communications centre that is written to the display unit of the cockpit. The identifier, for example a name or an identification number, of this communication centre, is not written to the display unit. Consequently, only the pilot who has written the new frequency knows which communications centre is concerned. However, if another crew member has to take over the communication link, because the pilot is having health problems or for any other reason, then the person who takes over the communication will not know which communications centre he has linked up with.
To enable a resumption of the communication by another crew member, the pilot in charge of communications can write the identifier of the communications centre manually to the display unit or on a piece of paper. This manual method is not only painstaking for the pilot but also risky because, many tasks have to be performed when changing air sectors and this handwritten recording makes for an additional workload.
To resolve this problem of absence of knowledge of the identifier of the communications centre during a resumption of communications, it has been envisaged to make an automatic search for the identifier of the communications centre corresponding to the communications frequency used. Now, given the large number of sectors of aeronautical space, no communications centre has a unique communications frequency. Indeed, several control centers may be assigned the same frequency by the air-traffic control authorities, if these centers are distant enough for there to be no problem of interference between aircraft communicating with these different communications centers. There is therefore no objective relationship between the frequency of a communications centre and the identifier of the corresponding communications centre.